Fix Pi constraint for -LONG_MIN adjustments

Fix Pi constraint for -LONG_MIN adjustments

-LONG_MIN == LONG_MIN so bad things will happen.
Example of JIT miscompile:

    function test($n) {
	if ($n + PHP_INT_MIN == 0) {
	    $n2 = (int) ($n + PHP_INT_MAX);
	    var_dump($n2);
	}
    }
    test(PHP_INT_MAX + 1);